This image of the Texas flag is in the Public Domain and can be used freely. If you use it on a webpage, a link to http://ourworldflags.com/Texas would be very much appreciated.

The flag of Texas

remain the naval flag of Texas until annexation, and was noted for
being "beneficial to our Navy and Merchantmen" due to its
resemblance to the US flag. Despite its unofficial status, the flag
remained well known inside the region and internationally as the
symbol of Texas.

The flag of Texas consists of a single blue vertical stripe and two
horizontal stripes of white and red. A white 5-pointed star, oriented
to have one point facing upward, is located at the center of the blue
stripe.

This is a modern photograph of the flag of Texas Flying on a flagpole.
If flown on the same flag pole as the United States flag, the Texas
flag should fly below the US flag. In this case, the Texas flag flies
on its own flagpole.